A frame assembly that includes at least two frame members that are connected to one another. A corner key cavity is formed at the outer sides of adjacent frame members and is shaped to cooperate with a corner key. The corner key cooperates with the corner key cavity to secure adjacent frame members to one another. The corner key cavity is formed at or near the outer perimeter of the joined frame members, and extends across a majority of the depth of the frame members. The frame assembly may include a number of frame members that, when secured to one another, define a window frame assembly.